Hawaii recently became the first state to raise the legal age for buying cigarettes to 21.

How old do you have to be to buy cigarettes? Increasingly, that depends on where you live.

In most places, you can still buy cigarettes if you're 18. Last month, however, Hawaii became the first state to raise the minimum age for tobacco purchases to 21. The California Senate has passed similar legislation, while a handful of states have raised the age to 19.

The push to keep cigarettes out of the hands of youngsters as long as possible has more momentum at the local level. Notably, New York raised the smoking age to 21 two years ago.

Needham, Mass., was the first locality to raise the age to 21, back in 2005. Needham was all alone in this regard until 2012. Since then, more than five dozen communities in Massachusetts alone have followed suit, representing 27 percent of the state's population, according to the Massachusetts Municipal Association.

"It's really powerful, it's growing," said Geoff Beckwith, executive director of the association, which has received funding from the Massachusetts Department of Public Health to provide technical assistance to cities exploring anti-smoking measures.

"Essentially, you're taking a product that's addictive and saying you have to wait until 21," Beckwith said. "The number of people who start smoking in their mid-20s is virtually zero."

A recent study found that teen smoking rates fell by nearly half in Needham in the first five years after the ordinance took effect, from 13 percent to 7 percent. By comparison, teen smoking in neighboring towns, which maintained the 18-year-old purchasing age, dropped by a fifth, from 15 percent to 12 percent.

"If we can keep the high school students from smoking, most of them will not become smokers," said John Schachter, a spokesman for the Campaign for Tobacco-Free Kids.

Not everyone is getting on board the wait-till-21 bandwagon, however. The borough council of North Plainfield, N.J., rejected an ordinance last month. It's pointless to ban sales to young adults who can simply cross the town line to buy cigarettes, said Council President Lawrence La Ronde, who said he would support a statewide measure.

Raising the legal age would simply increase the size of black market sales, said Bill Dembrowski, president of the California Retailers Association.

"The black market doesn't pay taxes and the black market doesn't care how old you are," he said. "We want to be able to sell a product legally to the right people, and this legislation discourages that."

Conservative groups such as the Mackinac Center and the Tax Foundation have estimated that close to 60 percent of the cigarettes sold in New York City have been smuggled in from other jurisdictions with lower taxes. A carton of cigarettes sold legally in New York is subject to $58.50 worth of excise taxes, compared with $3 in Virginia, making for an easy markup.

The tobacco industry hopes states and localities will defer to Congress on this issue. The other argument most often lodged against these bills is that it's doesn't make sense to prevent people from buying a legal product such as cigarettes at an age when they are old enough to vote or fight in a war.

"You can sign contracts, you can get married, you can go to war and lose an arm or lose an eye," Hawaii state Sen. Gil Riviere told the Associated Press. "You can come back and you're 20 years old and you can't have a cigarette."

Arguments about the difference in legal ages for different activities are unending. People are generally considered to be adults at 18, but the age gets adjusted up or down, depending on the percieved benefits for teenagers and society. States let kids drive before turning 18, for example, but make them wait until 21 to buy alcohol.

Health groups are confident that there is momentum pushing tobacco products in the same direction. The purchasing age has not historically been a big concern for anti-smoking advocates, who have focused more on raising taxes and creating smoke-free zones in work and public places.

But now they believe the idea is catching on. It seems particularly relevant at a time when e-cigarettes many be enticing young people to smoke.

E-cigarette smoking tripled among middle and high schoolers between 2013 and 2014 alone, according to the Centers for Disease Control. Last month, the American Medical Association adopted a policy encouraging laws banning sales of e-cigarette products to people under 21.

"Tobacco companies know that people are more likely to become addicted to smoking if they start at a young age," said state Sen. Ed Hernandez, sponsor of the California bill. "We can no longer afford to sit on the sidelines."

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